U.S. officials deny that they inadvertently revealed secret details about a proposed Israeli missile base when they put the $25 million project up for bid.

Department of Defense officials said Israeli officials had reviewed in advance and approved the 1,000 pages of specifications for the Arrow 3 anti-missile defense system base that were posted on a U.S. government website for contractors. The United States is paying for construction of the base. It routinely posts details of such projects so that contractors may estimate the cost of building them.

“We have a long-standing relationship with the Israeli Ministry of Defense, and we advertised the project in accordance with U.S. laws and regulations,” Brian Temple, the public affairs chief for the U.S. Army Corps of Engineers, Europe District – the branch of the U.S. government that worked out the arrangement with the Israeli government – said in an email.

He said Israel’s Ministry of Defense was responsible for determining how secret any project was and that “they determine whether they will be procured using classified or unclassified procedures.”

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“Allegations that we released classified information are false,” she said, adding that the instructions the United States had received made it clear that Israel viewed the matter as “an unclassified project.”

Israel continued to sharply disagree Thursday and to say the bidding proposal had revealed details that were to have been kept secret, including the location of the base, how the missiles are to be arrayed and even how thick the walls of the structures that would hold the missiles should be. One official had called the released details a blueprint for an attack.

"The Arrow 3 is not even formally operational. Why would we allow details of its composition to be published at this stage?" said an Israeli official close to the project. He declined to be identified because of the sensitivity of the project. He said Israel had expressed its shock at the publication of the base details to the United States through its own channels.

"We don’t think this is something they did on purpose, but it is absurd for them to say that we signed off on this," he said.

Israeli officials have said the release is especially worrying because the project is seen as a vital piece of defense plans in the event that Iran develops a nuclear missile capability.

The Obama administration has promised to build a state-of-the-art facility to house the Arrow 3, an anti-missile system that’s intended to intercept incoming rockets at a range of up to 1,500 miles. The missile is designed to maneuver in midair to chase its target.

The problems came when the United States treated the project as it does other unclassified Defense Department projects, making detailed specifications public so that contractors could see what was needed and bid on doing the work.

Israeli officials have said in the past that they were aware of the danger of outsourcing building projects to the United States, but the release of the bidding documents appears to have caught them off guard.

In Israel, this facility has been treated as so top secret that the military won’t officially confirm its location between Jerusalem and Ashdod, a span of only about 45 miles. The bidding documents place it at Tel Shahar.

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According to the bid requests, the Arrow 3 system will include six interceptors in vertical launch positions to be placed in the facility. A gantry crane would be needed to place additional missiles. The structures that would encase the interceptor system are to be constructed from high-grade concrete reinforced with steel mesh grids. Each missile silo is to have steel blast doors and a system to protect electrical wiring from the pressure created by a launch.